Rapid determination of ascorbate by ESR spectroscopy

Area of Science:

• Biochemistry
• Analytical Chemistry
• Spectroscopy

Background:

• Ascorbate (vitamin C) plays crucial roles in biological systems.
• Understanding ascorbate metabolism requires accurate detection methods.
• Electron Spin Resonance (ESR) spectroscopy can detect free radicals.

Purpose of the Study:

• To establish optimal conditions for determining ascorbate using ESR spectroscopy.
• To investigate the stability and distribution of ascorbate radicals in biological samples.
• To assess the applicability of ESR for studying ascorbate metabolism.

Main Methods:

• Electron Spin Resonance (ESR) spectroscopy was employed to detect ascorbate radicals.
• Optimal pH conditions were determined for measuring ascorbate, gallate, and caffeate radicals.
• Double logarithmic plots were used to correlate ascorbate radical intensity with concentration.
• ESR analysis was performed on homogenates from various mouse organs under alkaline conditions.

Main Results:

• Optimal pH for ascorbate radical measurement was determined to be 10.
• Ascorbate radicals showed instability at higher pH and neutral pH in brain and liver homogenates.
• A linear correlation was established between ascorbate concentration (0.03-10 mM) and radical intensity.
• Ascorbate was detected in various mouse organs.

Conclusions:

• The established ESR method is suitable for determining ascorbate radical concentration.
• Ascorbate radical instability in specific organs suggests the presence of metabolizing substances.
• This technique can be applied to study ascorbate metabolism and identify regulatory factors.